Metering fuel pump



April 29, 1952 w. E. LEIBING 2,594,662

METERING FUEL PUMP Filed DEC. 15, 1948 el* Y im Patented Apr. 29, `1952UNITED'A STATES ATENT OFFICE METERING FUEL PUMP William E. Leibing, LosAngeles,-alif.

Application December 13, 1948, Serial No. 65,031

Claims.v (Cl. 10S-161) Y f lating the richness of the mixture so thatthe y proper proportions of fuel and air can be admitted to `the engine.Such adjustments are ordinarily made to meet sea level conditions;

that is, the fuel delivery at full load and the fuel delivery at idlingare adjusted so that the engine operates at a maximum efficiency underthe barometric pressure existing at sea level. If the engine as adjustedis later operated at high elevation the lower barometric pressure hasthe effect of reducing the proportion of air admitted for combustion,with the result that the fuel air mixture becomes too rich. The problemof making proper correction for altitude is complicated by the fact thatit has been found that substantially no correction is required foridling. It is known that the iiow of air through arestriction increasesin proportion to the pressure difference across the restriction up to acertain point. Thus air flow through a throttle valve of an engine underthe action of manifold vacuum pressure increases in proportion to thevacuum up to about fourteen inches of mercury, but higher vacuumpressures do not appreciably increase the flow at all. Hence, thethrottle valve on the internal combustion engine which normally idlesatsea level with about twenty inches of mercury vacuum in the intakemanifold will pass the same amount of air at six thousand feet altitudeas it will at sea level, and therefore the same amount of fuel should bedelivered to theengine when idling at six thousand feet as when. idlingat sea i level.

Accordingly, it is the principal object of this generally designated-I1.

elements includes a radially-movable piston I8,y a flexible sealingVdiaphragm I9, and a compres-V invention to provide a metering fuel pumpfor embodies `certainimprovements ovenmy copend-- z ing applications,Serial No. 783,106, filed Decerrr z. ber 1, 1947; and Serial No. 7,250,filed February 1 9, 1948, which matured into Patent No. 2,557,508 onJune V19, 1951.

Another Objectis to provide a sealed metallic bellows or the likeoperable. through a yoke to reduce the output of the fuel pump whenatmospheric pressure is reduced.

Other objects hereinafter.

In the drawings:

llgure--ly is -a sectional planview showing a preferred embodiment of`my invention.

Figure 2 is a transverseA sectional elevation. taken substantiallyonuthe lines 2-2 asshown in Figurel.

Figure3 is a longitudinal section taken substantially on the lines 3 3as shown in Figure l.

' Figure 4 is a perspective view-showing a preferred construction of theyoke.

Referring to the drawings, a easing I is provided with spaced alignedbearings II and I2 for supporting rarotor shaft I3 adapted to be drivenfrom its-projecting endY I4. The projecting end I isi-provided with asuitable keyway I5 so that the shaft may be driven in timed relationwith the rotation of the crank shaft or cam shaft of an internalcombustion engine.- A rotor I6 is fixed on the shaft and turns withinthe casing Ill.

Thesirotor is provided with a single or double` series of `positivedisplacement pump elements Each of these pump sionspring 20. A sleeve 2lencircles the rotor I6 and is adapted to rotate therewith. The sleeve 2|is carriedfon a bearing 22 within a ring 23 which is pivotally mountedon the housing at 24.

Clearance-is `provided within the housing so that thefring 23- can beshifted about its pivotal support 211. Such shifting movement of thering 23 and. sleeve 2| relative to the rotor I6 develops eccentricity ofthe sleeve 2l and hence the lindividual pump pistons I9 reciprocateradially as the rotor I6 isturned. rlfhis reciprocation is used to pumpfuel from an inlet 25 to spaced outlets .l

.26 and 21. The passage of the fuel vfrom the inlet- 25 to the outlet 26is by way of the passageway A23, chamber 29, inlet passage 30 and port3I in the sealing washer 32. The discharge from the series of pump unitsIIon the left side of the rotor as viewed in Figure 3 occurs throughoutlet port 33 in the washer32outlet passage 34 and chamber 35.; The`member 36 which supports the sealing washenlgmaybe; resilientlysupported on and.Y advantages will appear the springs 31. The right handseries of pump units |1 as shown in Figure 6 act to pump fuel from theinlet 25 to the outlet 21 by way of the sealing washer 38. The portingand series f passageways for the sealing washer 38 are similar to thosedescribed in connection with the sealing washer 32.

Means are provided for shifting the ring 23 in response to variations invacuum pressure in the inlet manifold of the internal combustion engine.The vacuum pressure is communicated to the vacuum chamber 39 by way ofthe inlet 40. The flexible diaphragm 4| at one end of the chamber 39 isconnected to a control element 42 which extends through the diaphragm 4|and forms a seal therewith. The control element 42 is provided with acentral projection 43 which carries a transverse pin 44. A lever 45which comprises a pair of duplicate elements 46 is pivoted at one end tothe pin 44 and at the other end to the pin 41. The pin 41 is mounted inthe member 48 which is pivotally supported in the housing I9 on thepivot pin 49. The spring 50 acts to maintain the member against theadjustable stop A link 52 is pivotally connected to the lever at 53 andto the ring 23 at 54. Accordingly, movement of the control member 42moves the lever 45 about the pivot pin 41 and hence shifts the ring 23about its pivotal support 24. A spring 55 is mounted within the chamber39. This spring engages the member 42 at one end and a stop collar 5S atthe other end. An adjustable set screw 51 extends through the wall ofthe casing to contact the stop collar 56.

A yoke member generally designated 58 is formed of a pair of endsections 59 and 60, each having an oval shaped opening 6I. The member 59is provided with end walls 62 and 53 having tabs 64. The tabs 64 areadapted to extend through apertures 85 provided in the member 60, andthe yoke assembly is completed by the insertion of suitable cotter pins66 Within the openings 61 to retain the members 59 and 60 in assembledrelationship about the rotor I6. The oval shaped openings 5| aresufficiently large so that the yoke does not contact the rotor at anytime. A pair of ears 58 are provided on the end wall 63, and these earsare pivotally mounted on the pin 44 so that the yoke 58 is pivotallyconnected to the control member 42.

A metallic seal bellows 19 is mounted within the housing I0 and isattached to the end wall 62 of the yoke 58 by means of a screw 1| orother suitable attachment means. The location of the bellows 1D isdiametrically opposed to the location of the diaphragm 4|. The outer endof the bellows is carried on a threaded pin 12 which extends outwardlythrough the wall of the housing and is provided with a lock nut 13. Thesealed bellows 10 may contain air if desired, but I prefer to use a gaswith a low coefficient of expansion such as, for example, helium gas orhydrogen gas.

An arm is xed to the pivot shaft 49 at a location outside of the housing|0. This armv is adapted to be actuated by a suitable rod (not shown) inorder to increase the rate of delivery of fuel under cold startingconditions. Counterclockwise movement of the lever 15 as shown in Figure2 moves the tting 48 to compress the spring 59 and to move the lower endof the lever 45 toward the left, thereby causing the links 52 to movethe ring 23 to increase its eccentricity.

In operation the rotor shaft |3 is driven in timed relation with theengine and turns the rotor I6 and sleeve 2| within the nonrotary ring23. The position of the ring 23 determines the amount of eccentricity ofthe sleeve 2|, and accordingly regulates the stroke of the individualpump units |1 as they rotate with the rotor I6. When the vacuum pressurein the engine manifold is high relatively little fuel is required. Thus,when the engine is idling the fuel requirements are at a minimum and themanifold Vacuum pressure is high. This vacuum pressure is transmitted tothe vacuum chamber 39. Atmospheric pressure within the casing acts onthe exposed area of the diaphragm 4| and moves the control member 42 tothe right as shown in Figure 2 against the action of the spring 55.Atmospheric air reaches the interior of the housing I0v by way of thescreen plug assembly generally designated 14. When the engine isequipped with a super charger the screen plug assembly 14 is removed sothat the interior of the housing I0 may be connected with the airinduction system between the super charg'er and the throttle valve ofthe engine (not shown), so that the pressures within the housing arethose pressures which are available to the engine.

The set screws 51 and 12 are adjusted so that the lower vacuum pressure,when the engine operates at full throttle and full load at sea level, iseifective to provide the proper rate of fuel delivery.

When idling at sea level there is a balance between the spring 55 plusthe effect of the bellows 19 on one hand and the resultant thrust onthe. v diaphragm 4| under idling conditions on the oth-Y er hand. Theidling position of the control member 42 as thus determined does notchange when the engine is operating at high altitude be- Y fuel isdelivered to the engine when idling, re- I' gardless of elevation.

The diaphragm pump elements |1 which op-` Y l erate within the rotor arespring actuated towardv their outer position, and as each of the springsare of substantially equal tension it follows that the sleeve 2| alwaystends to center itself around the rotor, for when so centered allsprings 20 within the rotor I6 are under equal compression.

To shift the sleeve2| to the position of maximum eccentricity as shownin Figure 2 requires a considerable effort of spring 55 and of bellows19. The spring 55 and bellows 19 are correspondingly set at sea level tomaintain the proper eccentricity of the sleeve 2| to deliver thecorrectY amount of fuel to the engine for full power. Accordingly, whenthe engine operates under full load at a high altitude the bellows 10becomes considerably weaker in that the internal pressure is greaterthan the external pressure. Accordingly, the yoke 58 will be shiftedtoward the right as viewed in Figure 2, reducing the eccentricity of thesleeve 2| and therefore reducing the amount of fuel pumped. Since theengine is operating at full load, the manifold vacuum pressureapproaches zero, and hence the diaphragm 4| plays no part in positioningthe yoke 58. It has been found from experience that intermediatepositions between full throttle and idling position are well compensatedfor by the mechanism disclosed, and that once both limits or extremepositions are chosen the intermediate positions operate satisfactorily.

A small amount of grow of the bellows upon application of heat is adesirable feature for it-acts as an automatic enrichment means for theeng-ine upon cold starting conditions. By the proper selection of thesize of the bellows any greater or lesser amount of correction foraltitude can be obtained, and by using different gases within thebellows different degrees of automatic cold start effectiveness can behad.

Having fully described my invention, it is to be understood that I donot wish to be limited to the details herein set forth, but my inventionis of the full scope of the appended claims.

I claim:

1. In a pump, the combination of a housing; a rotor mounted to turn inthe housing; a plurality of positive displacement pump elements mountedfor radial movement on the rotor; a rotatable sleeve encircling therotor and cooperating with each of said pump elements; means including amovable member in the housing adapted to shift the sleeve to vary thestroke of the pump elements; vacuum operated means adapted to shift theposition of said movable member and thereby vary the rate of delivery offuel from said pump elements; altitude correction means including anexpansible sealed member mounted within the housing on the opposite sideof the rotor from said vacuum operated means; and means connecting thesealed member with said movable 6 able member in the housing adapted toshift the ring; vacuum operated means adapted to shift the position ofthe member and thereby vary the rate of delivery of fuel from said pumpelements; altitude correction means mounted within the housing on theopposite side of the rotor from said vacuum operated means fordecreasing the fuel delivery rate from said pumpelements, said meansincluding a sealed bellows connected with said movable member wherebymovement of the control member under high vacuum conditions is resistedby lengthening of the bellows.

member whereby the sealed member may act in tension to oppose the actionof the vacuum operated mea-ns under high vacuum conditions and to shiftthe movable member in a direction to -reduce the stroke of the pumpelements under low vacuum conditions.

2. In a pump, the combination of a housing; a rotor mounted to turn inthe housing; a plurality of positive displacement pump elements mountedfor radial movement on the rotor; a rotatable sleeve encircling therotor and cooperating with each of said pumps; means including a movablemember in the housing adapted to shift the sleeve to vary the stroke ofthe pump elements; vacuum operated means adapted to shift the positionof said movable member and thereby vary the rate of delivery of fuelfrom said pump elements; altitude correction means including a sealedbellows mounted within the housing on the opposite side of the rotorfrom said vacuum operated means and coaxially therewith; and a yokeconnecting the bellows member with said movable member whereby thebellows member may act in tension to oppose the action of the vacuumoperated means under high vacuum conditions and to shift the movablemember in a direction to reduce the stroke of the pump elements underlow vacuum conditions.

3. In a fuel pump, the combination of a hous-nI ing; a rotor mounted toturn in the housing; a plurality of positive displacement pump elementsmovably mounted on the rotor; a nonrotary ring in the housing having arotatable sleeve thereon encircling the rotor and cooperating with eachof said pumps, the ring and sleeve being shiftable to vary thefstroke ofthe pump elements; a movring and sleeve being shiftable to vary thestroke' 4. In a fuel pump, the combination of a housing; a rotor mountedto turn in the housing and driven by the engine; a plurality of positivedisplacement pump elements movably mounted on the rotor; a rotatablesleeve encircling the rotor and cooperating with each of said pumps;means including a movable member in the housing adapted to shift thesleeve to vary the stroke of the pumpv elements; means actuated byvacuum pressure adapted to shift the position of said member vandthereby vary the rate of delivery ci' fuel from said pump elements; andaltitude correction means including a sealed bellows mounted within thehousing on the opposite side of the rotor from said vacuum operatedmeans and connected with said movable member whereby movement of thecontrol member under high vacuum conditions is resisted by lengtheningof the bellows.

5. In a fuel pump, the combination of a housing; a rotor mounted to turnin the housing 'and driven by the engine; a plurality of positivedisplacement pump elements movably mounted on the rotor; a nonrotaryring in the housing having a rotatablev sleeve thereon encircling therotor and cooperating with each of said pumps, the

of the pump elements; a movable member in the housing adapted to shiftthe ring; vacuum operated means adapted to shift the position of saidmember and thereby vary the rate of delivery of fuel from said pumpelements; altitude correction means including a sealed bellows mountedwithin the housing on the opposite side of the rotor from said vacuumoperated means; and a yoke connecting the bellows member with saidmovable member whereby the bellows member may act in tension to opposethe action of the vacuum operated means under high vacuum conditions andto shift the movable member in a direction to reduce the stroke of thepump elements under low vacuum conditions.

WILLIAM E. LEIBING.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

